High frequency transmission line

ABSTRACT

A line for transmitting high frequency electrical signals, including video signals; the line being used to simultaneously transfer and radiate energy and including shielding means for reducing losses.

United States Patent [72] lnventor Otto Breitenbach Nurnberg, Germany[21 Appl. No. 868,496 [22] Filed Oct. 22, 1969 [45] Patented Feb. 16,1971 [73] Assignee Kabel-und Metallwerke GutehoffnungshutteAktiengesellschatt Hannover, Germany a corporation of Germany [32]Priority Oct. 23, 1968 [3 3 Germany [31] P 1,804,679

[54] HIGH FREQUENCY TRANSMISSION LINE 7 Claims, 1 Drawing Fig.

[51] lnt.Cl. ....H0lb 11/06 [50] Field ot'Search 174/32, 36,113.113.2,115,1l7,117.4,27;333/96 [56] References Cited UNITED STATESPATENTS 1,928,992 10/1933 Clark etal. l74/28UX 2,804,494 8/1957 Fentonl74/27X Primary Examiner- Laramie E. Askin Assistant Examiner-A. T.Grimley Attorney-Philip G- Hilbert ABSTRACT: A line for transmittinghigh frequency electrical signals, including video signals; the linebeing used to simultaneously transfer and radiate energy and includingshielding means for reducing losses.

PATENIED FEB] 6 I971,

INVENTOR. B 0H0 Breifenbach ATTORNEY It has been proposed to providetransmission lines for transmitting high frequency signals stationarytransmitters to mobile receivers or from -mobile transmitters tostationary receivers; more particularly for the transmission of videosignals from stationary television camerasto receivers in mobilevehicles. Such lines should conduct the high frequency energy withminimal losses and have the usual radiation characteristic.

For this purpose, symmetrical, unshielded high frequency lines, known astwin-lead transmission lines have been used. Such lines have losses andradiation characteristics that are strongly dependent onenvironmental-influences and weather conditions; particularly when theyare mounted on open, flat subsurfaces.

Also known in the art is the radiating, approximately coaxial line, alsoknown as the slot line, where the outer conductor envelopes theconcentric insulation of the inner conductor over only a portion of theperiphery thereof. The radiation that results through the slot thatremains in the outer conductor, gives rise a rapid decrease in fieldstrength with increasing distance from the line. To achieve sufficientsignal strength for the receiver, a correspondingly large amount ofenergy must be supplied to the line. This energy, however, is limited bythe dimensions of the line.

Alternatively, the receiver must have high sensitivity, which in turnwould increase its reception of noise radiation. A further alternativewould be to give the high frequency line large dimensions. However, theline would be much heavier, expensive to produce and thereforeuneconomical.

Accordingly, an object of this invention is to provide an improved highfrequency transmission line; particularly adapted for transmitting videosignals and having a construction which allows for radiation of the highfrequency energy in the desired direction without impeding the same.

Another object of this invention is to provide a transmission line ofthe character described which includes shielding means such that lossesare materially reduced with distance, whereby the distance betweenreceiver and transmitter may be effectively increased or the sensitivityof the receiver may be reduced.

Still another object of this invention is to provide a transmission lineof the character described which comprises tubing of synthetic resinmaterial on which linear and shielding conductors are mounted inspecific relationship to each other; the line being mechanically stableunder all conditions of installation and use. t

DESCRIPTION OF THE DRAWING The single FIG. is a perspective view showinga high frequency transmission line embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS ries embedded therein alongitudinally extending linear conductor 14 such as a wire.

. Shielding means, generally indicated at 15 is disposed in wall 13 in aposition diametrically and symmetrically related to linear conductor 14.Shielding means 13 comprises metal strips 16 having a thickness of about0.1 mm., formed of copper, aluminum or the like and being in edgeabutting relation.

The shielding strips 16, as well a conductor 14 are located in situduring the extrusion of tubingll. The strips 16 may be precorrugated asindicated at 17, to afford flexibility to the finished line,particularly when the same is reeled and unreeled. Further, the stripsl6'may be formed with longitudinally spaced, longitudinal slits, notshown to increase the flexibIlity characteristic of the line. Also, thewear conductor 14 may be precorrugated, to aid flexibility.

The shielding means 13 may extend over an angle of from about to aboutthe same being symmetrically related to the linear conductor 14. Also,the strips 16 may have their edges in slightly spaced relation; or thestrips may be replaced by a unitary wide-strip subtending a similarangle.

The wire 14 may be replaced by stranded conductors, narrow flatconductors, and the like. Also, conductor 14 may be embedded in the wallproper 13 rather than in the rib 12.

lclaim: I q

l. A high frequency transmission line comprising dielectric tubing, aconductor extending longitudinally on a wall portion of said tubing andparallel to the axis thereof, and shielding conductor means extendinglongitudinally in another wall portion of said tubing and parallel tothe axis thereof.

2. A transmission line as in claim 1 wherein-said shielding means isdiametrically and symmetrically related to said conductor.

3. A transmission line as in claim 2 wherein said conductor iscorrugated along the length thereof.

4. A transmission line as in claim 1 wherein said shielding meanscomprises a plurality of metal strips in edge abutting relation to eachother.

5. A transmission line as in claim 4 wherein said strips are a

1. A high frequency transmission line comprising dielectric tubing, aconductor extending longitudinally on a wall portion of said tubing andparallel to the axis thereof, and shielding conductor means extendinglongitudinally in another wall portion of said tubing and parallel tothe axis thereof.
 2. A transmission line as in claim 1 wherein saidshielding means is diametrically and symmetrically related to saidconductor.
 3. A transmission line as in claim 2 wherein said conductoris corrugated along the length thereof.
 4. A transmission line as inclaim 1 wherein said shielding means comprises a plurality of metalstrips in edge abutting relation to each other.
 5. A transmission lineas in claim 4 wherein said strips are transversely corrugated along thelength thereof.
 6. A transmission line as in claim 5 wherein said stripsare formed with successive longitudinal slits along the length thereof.7. A transmission line as in claim 4 wherein said strips extend over anangle of from about 90* to about 120*.